Actionscript 2 Recalling variables outside of a function.

Question

Hi, I'm having a little trouble recalling variables set within a frame from a function. I'm using Action Script 2.0 using Adobe Flash CS4, but am getting in practice of not placing codes on movie clips and keeping it on the main stage. On a frame on the time line I have the following:

var mcJumping:Boolean = false;    
function isJump():Void {
 trace( _root.mcJumping );
    //or I've tried
    trace( mcJumping );
}

isJump();

In the output the trace shows "undefined". Also is there a easier way of recalling variables I have on the a frame? or even in a movie clip? Thank you in advance for your help.